We’ve reached the point where our Hybrid Vacuum-tube mic preamp prototype works, and now we need to put everything together in an easy-to-assemble package, in other words a complete kit. So it’s time to design the Printed Circuit Board. Continuing our Mic Preamp Design Adventure… see past articles:

Here’s an idea for a cheap solder fume extractor… helps keep away the smokey burning flux away from your face. You just need a small 12V computer fan (real cheap, or look in your junk computer parts pile), and a lab power supply, or 12V DC Adapter. Add a filter

Found this in my pile of parts. I can’t even remember where I bought them, or if they’re still working. It looks cool though, don’t you agree? Here’s more information about these TransAmps for those interested…

Found some low voltage tubes on eBay, and that started a curiosity in researching and learning more about the history of these “space charge” tubes. https://en.wikipedia.org/wiki/Space_charge Basically, Space Charge tubes are designed to operate using low voltages, instead of using high voltages

Yay! NK-72DI Mic Preamp kits are now shipping. I’m still slowly ramping up, but this is a milestone. I’m happy. Also, the assembly guide PDF is also finished and will be available on the website for download. I still need to update